Articulating torqueable hollow device

ABSTRACT

An articulating mechanism for use in a medical device, such as an endoscope or a catheter, includes a series of stacked links disposed adjacent to one another and movable with respect to each other. Each link includes a front face tapered to a pair of pivot points and a rear face defining a wedge shaped recess for receiving the pivot points of the adjacent link. Pull-wires provide tension and hold the staked links together while also allowing for controlled bending of the distal portion by movement of one or more of the pull-wires.

CROSS-REFERENCE TO RELATED CASES

This application claims priority to, and the benefit of Provisional U.S.Patent Application Ser. No. 60/930,748, filed May 18, 2007, the entiretyof which is incorporated herein by reference.

TECHNICAL FIELD

The present invention generally relates to medical devices such asendoscopes and catheters. More specifically, the invention relates toflexible medical devices that are bendable and steerable in order tonegotiate and access various areas within a patient.

BACKGROUND INFORMATION

It has become well established that there are major public healthbenefits from early detection and treatment of disease of internalorgans (such as the colon, esophagus, stomach, urethra, bladder, ureter,kidney, lungs, bronchi, uterus, and other organ systems) and of variousbody passageways (such as the alimentary and excretory canals andairways). Early detection of such diseases can be accomplished byperiodic medical examinations aided by modern medical procedures anddevices such as an endoscope. A conventional imaging endoscope generallycomprises a flexible tube with a fiber optic light guide that directsilluminating light from an external light source to the distal tip whereit illuminates the region inside the body of the patient to be examined.Frequently, additional optical components are incorporated to adjust thespread of the light exiting the fiber or fiber bundle and the distaltip. An objective lens and fiber optic imaging light guide communicatingwith a camera at the proximal end of the endoscope, or an imaging camerachip at the distal tip, produce an image that is displayed to theoperator. In addition, most endoscopes include one or more workingchannels through which medical devices such as biopsy forceps, snares,fulguration probes, and other tools may be passed.

Some endoscopes and electrophysiology catheters can steer or deflect thedistal tip of the endoscope to follow the pathway of the anatomy underexamination such as the colon, bladder, kidney, and heart. Deflection orarticulation is often a desirable characteristic in these types ofmedical devices to minimize friction force and trauma to the surroundingtissue, and to survey targeted examination sites. Navigation of theendoscope through various areas within a patient improves the success ofthe examination and minimizes pain, side effects, risk, or sedation tothe patient.

In order to achieve active deflection at the distal flexible portion ofthe device, most endoscopes use a force created on one end of thedevice, usually at a handle. The three is then transmitted to thearticulation section by control cables or pull-wires. The pull-wires arecarried within the endoscope shaft connecting the distal end to a set ofcontrols in the handle. By manipulating the controls, the operator isable to steer the distal portion of the endoscope during insertion anddirect it to a region of interest within the body of the patient.

The mechanism of deflection varies amongst steerable endoscopes andcatheters. Some articulating sections are made of elastic elements, suchas for example, Pebax®. When the force is applied through thepull-wires, one side of the element can deform (i.e., compress orstretch) resulting in bending. The consistency of bending plane of thesedevices would depend on such factors as, for example, materialhomogeneity, or the manufacturing process, for example molding orextrusion. Therefore, the bending consistency with such devicestypically is far less than ideal. Also, these devices generally are notdesigned to transmit a torque from one end to the other. They tend totwist when torqued.

Other articulating designs consist of many separate elements, links,each of which has a pivoting point. Under the applied force, each linkwould turn around a pivoting point relative to each other. Such deviceskeep the bending plane much more consistently.

There are many design and performance challenges inherent in these knowndevices. Some of these challenges include achieving planar deflection atthe tip as well as preventing the shaft from buckling or forming aseries of “S” shapes from the tension of pull-wire mechanisms. Otherchallenges include being able to keep an individual bend in one plane,achieving the appropriate amount of angular deflection, and achievingmultiple directions of deflection.

Typically, flexible endoscopes are very expensive medical devices.Because of the expense, these endoscopes are built to withstand multipleuses upon many patients and repeated disinfections. Conventionalendoscopes are generally built of strong composite material structuressuch as metals and plastics that do not degrade under repeated cleaningand high temperatures. These material structures decrease theflexibility of the endoscope and can compromise patient comfort.Furthermore, conventional endoscopes are typically complex and fragileinstruments that frequently need expensive repair as a result of damageduring use or during a disinfection procedure.

SUMMARY OF THE INVENTION

To address or overcome problems with known flexible endoscopes, theinvention relates generally to low cost flexible endoscopes that can beused for a single procedure and then disposed, thereby eliminating theneed for preparation and cleaning between uses. A low cost endoscopeaccording to the invention could be packaged sterile or disinfected andbe capable of being used for a single procedure without endoscopepreparation, and then discarded after the single use. The endoscopecould include one or more of the following features, as compared tocurrent flexible endoscopes: better navigation and tracking, a superiorinterface with the operator, improved access by reduced frictionalforces upon the lumenal tissue, increased patient comfort, greaterclinical productivity and patient throughput than is currently availablewith a conventional endoscope, a lower risk of cross-contamination, andthe ability to be used across more procedures.

It thus is desirable to provide new devices with active controlledbending and methods for using such devices and also for making flexibleshafts for medical devices. It is particularly desirable to provide suchdevices and methods that would achieve planar deflection at the tip aswell as preventing the shaft (non-deflecting portion) from buckling orforming a series of “S” shapes from the tension of pull wire mechanismsin comparison to prior art devices. It also is desirable to provide sucha device that would be able to keep an individual bend in one plane,achieve the appropriate amount of angular deflection and achievemultiple directions of deflection. Such deflection devices are simplerin construction and less costly than prior art devices, and such methodsdo not require highly skilled users to utilize the device.

A particular embodiment of the present invention relates to anarticulating mechanism for use in a medical device, and the mechanismincludes a series of stacked links disposed adjacent to one another'andmovable with respect to each other. Each link has a front face taperedto a pair of pivot points and a rear face defining a wedge shaped recessfor receiving the pivot points of the adjacent link. One or morepull-wires provide tension, holding the stacked links together whilealso allowing controlled bending of the distal portion by movement ofthe one or more of the pull-wires.

In an alternative embodiment of the present invention, an articulationmechanism for use in a medical device includes a series of stacked linksdisposed adjacent to one another and movable with respect to each other.Each link has a front face tapered to a pair of pivot points and a rearface defining a wedge shaped recess for receiving the pivot points ofthe adjacent link radially offset from the pivot points, allowing formultiple planes of deflection. At least one pull-wire provides tensionand holds the stacked links together while also allowing controlledbending of the distal portion by movement of the pull-wire(s).

In another alternative embodiment of the present invention, anarticulation mechanism for use in a medical device includes a firstarticulation section with a first series of stacked links disposedadjacent to one another and movable with respect to each other. Eachlink has a front face tapered to a pair of pivot points and a rear facedefining a wedge shaped recess for receiving the pivot points Of theadjacent link. The articulation mechanism also includes a secondarticulation section. The second articulation section includes a secondseries of stacked links disposed adjacent to one another and movablewith respect to each other, each link having a front face tapered to apair of pivot points and a rear face defining a wedge shaped recess forreceiving the pivot points of the adjacent link. The wedge shapedrecesses of the first articulation section are radially offset from thewedge shaped recesses of the second articulation section allowing formultiple planes of deflection.

The articulating mechanism can further include a control cam. Theproximal ends of the at least one pull-wire is connected to the controlcam. When the user rotates the control cam, tension is applied to the atleast one pull-wire thereby deflecting the distal end of thearticulation mechanism.

The articulation mechanism can further include an outer sleeve disposedon the outside of the articulation mechanism to provide a smoothexterior surface. A variety of lubrications and/or drug coatings canalso be included on the outer sleeve to reduce friction or treatportions of the patient being examined.

The articulating mechanism can further include radiopaque markers orradiopaque materials to ensure proper positioning of the articulatingmechanism.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the nature and operation of variousembodiments according to the present invention, reference is made to thefollowing description taken in conjunction with the accompanying drawingfigures wherein like reference characters denote corresponding partsthroughout the several views and wherein:

FIG. 1 depicts a link used to form an articulation mechanism inaccordance with an embodiment of the present invention;

FIG. 2 depicts a schematic rendering of an articulation mechanism formedby stacking a series of the links shown in FIG. 1;

FIG. 3 depicts an enlarged schematic rendering of the distal portion ofthe articulation mechanism shown in FIG. 2;

FIG. 4 depicts an enlarged schematic rendering of the proximal portionof the articulation mechanism shown in FIG. 2;

FIG. 5 depicts a schematic rendering of the articulation mechanism shownin FIG. 2 bent in the upward direction;

FIG. 6 depicts a link used to form an articulation mechanism inaccordance with an alternative embodiment of the present invention;

FIG. 7 depicts a schematic rendering of an articulation mechanism formedby stacking a series of the links shown in FIG. 6;

FIG. 8 depicts a link used to form an articulation mechanism inaccordance with an alternative embodiment of the present invention;

FIG. 9 depicts a link used to form an articulation mechanism inaccordance with an alternative embodiment of the present invention;

FIG. 10 depicts a partial cross-section of an articulation mechanismformed by stacking a series of the links shown in FIG. 1 in a deflectedposition; and

FIG. 11 depicts a partial cross-section of an articulation mechanismformed by stacking a series of the links shown in FIG. 9 in a deflectedposition.

DESCRIPTION

The present invention relates to a flexible articulation mechanism to beused in steerable endoscopes and catheters. These medical devices allowan operator to access and view internal body anatomy of a patient aswell as to insert surgical instruments into the patient's body. Inaddition, these devices may include integrated diagnostic andtherapeutic capabilities to allow the operator to treat the patient in asingle procedure. An articulation mechanism according to the presentinvention can be sufficiently inexpensive to manufacture such that thedevice can be considered a single use, disposable item. All relativedescriptions herein such as top, bottom, left, right, up, and down arewith reference to the figures, and thus should not be construed in alimiting sense.

One embodiment of articulation mechanism 10 according to the presentinvention is made of a series of stacked links 12 that are positionedadjacent to one another, defining an inner lumen 14 and movable withrespect to each other. Referring now to FIG. 1, a link 12 according toone embodiment of the present invention includes a front face 16 and arear face 18. Each link may be deep drawn, rolled and welded, stamped,injection molded, or otherwise formed of stainless-steel or otherbiocompatible material that allows the link 12 to be rigid while havinga thin wall profile in order to maximize the size of the inner lumen 14.

The front face 16 of the link 12 includes a pair of oppositely arrangedengagement surfaces that bisect the link 12 and define a pair of pivotpoints 20 that engage the corresponding rear face 18 of an adjacent link12, The pivot points 20 are rounded over forming substantiallycylindrical surfaces that serve as bearings. The front face 16 of thelink 12 further includes two tapered sections 22 that are angledproximally away from the pivot point 20. The two tapered sections 22 areoriented at an angle of A° with respect to the longitudinal axis 24 ofthe link 12. The terms proximal and distal require a point of reference.In this application, the point of reference is the perspective of theuser. Therefore, the term proximal will always refer to an area closestto the user, whereas distal will always refer to an area away from theuser.

Similarly, the rear face 18 of the link 12 includes two sloped sections26 that are angled distally away from a relatively flat surface 28 ofthe rear face 18 forming a wedge shaped recess 30 with a vertex 32 forreceiving the pivot points 20 of the adjacent link 12. As with thetapered sections 22 at the front face 16 of the link, the slopedsections 26 of the rear face 18 are oriented at an angle of B° withrespect to the longitudinal axis 24. Additionally, the vertex 32 isrounded to form a substantially cylindrical surface to engage therounded over surface of the pivot points 20.

A plurality of wire channels 34, 36, 38, 40 are integrally formed in thelink 12 itself or otherwise disposed on the inner surface 42 of the link12. The wire channels are radially spaced at predetermined distancesaround the circumference of the link 12. As shown in FIG. 1, channels 36and 40 are positioned at the pivot points 20, while channels 34 and 38(not shown) are rotated 90° with respect to channels 36 and 40.

Referring now to FIGS. 2-5, the articulation mechanism 10 is created bystacking a number of links 12 a, 12 b, 12 c, etc., such that that thepivot points 20 of each link 12 are aligned with the vertex 32 of theadjacent link 12. Locking pull-wires 46 and 50 disposed in wire channels36 and 40 provide tension to hold adjacent links 12 a, 12 b, 12 c, etc.,together while pull-wires 44 and 48 are components of the controlmechanism for bending the articulation mechanism 10 in the desireddirection.

The control mechanism includes pull-wires 44 and 48 and a control cam52. The proximal ends of pull-wires 44 and 48 are connected to thecontrol cam 52 and the distal ends of the pull-wires 44 and 48 areconnected to the distal end 54 of the articulation mechanism 10 (FIG.3). As shown in FIG. 5, when the user rotates the control cam 52 in theclockwise direction as indicated by line C on, tension is applied topull-wire 44, and tension is released from pull-wire 48, therebydeflecting the distal end 54 of the articulation mechanism in an upwarddirection. Conversely, when the user rotates the control cam 52 in acounter-clockwise direction, tension is applied to pull-wire 48 andreleased from pull-wire 44, thereby deflecting the distal end 54 in adownward direction.

The deflection capability of the articulation mechanism 10 is a functionof the difference between angels A and B and the number of links N,which can be represented by the formula: deflection angle=(A−B)/2×(N−1).For example, in the embodiment shown in FIG. 2, if angle A is 140°,angle B is 100°, and there are 11 links including the first and lastlink the deflection would be 200°. The radius of deflection is afunction of the angle difference and the length of the link (i.e,shorter links will produce a smaller bend radius).

A flexible outer sleeve may be disposed on the outside of thearticulation mechanism 10 to provide a smooth exterior surface. Theouter sleeve can be made from soft, thin polyurethane, LLDPE, silicon,pellethane, polyurethane, or other approved biocompatible materials suchas polyethylene, polypropylene or polyvinyl alcohol. Additionally, theouter sleeve can be coated with a hydrophilic, lubricious coating suchas HYDROPASS™ hydrophilic coating available from Boston ScientificCorporation, of Natick, Mass., and described in U.S. Pat. Nos. 5,702,754and 6,048,620, which are herein incorporated by reference. Additionally,the outer sleeve canoe coated with a drug agent to treat internal bodytissues.

To ensure proper positioning, it is desirable for the articulationmechanism 10 to be visible using fluoroscopy, echocardiography,intravascular ultrasound, angioscopy, or another means of visualization.Where fluoroscopy is utilized, any or all of the articulation mechanismmay be coated with a radiopaque material, or a radiopaque marker may beincluded on any portion of the device that would be useful to visualize.One example of a radiopaque material that can be used is barium sulfate.Radiopaque markers can be made from any of a number of materialsincluding, for example, gold, platinum, or tungsten.

Referring now to FIG. 6, a link 112 according to an alternativeembodiment of the present invention is shown. The link 112 performssubstantially the same function as the link 12 described above, andtherefore like reference numerals preceded by the numeral “1” are usedto indicate like elements.

In this embodiment the front face 116 of the link 112 includes a pair ofoppositely arranged engagement surfaces that bisect the link 112 anddefine a pair of pivot points 120 that engage the corresponding rearface 118 of an adjacent link 112. The pivot points 120 are rounded overforming substantially cylindrical surfaces that serve as bearings. Thefront face 116 of the link 112 further includes two tapered sections 122that are angled proximally away from the pivot point 120.

The rear face 118 of the link 112 includes two sloped sections 126 thatare angled distally away from a relatively flat surface 128 of the rearface 118 forming a wedge shaped recess 130 with a vertex 132 forreceiving the pivot points 120 of the adjacent link 112. Unlike theembodiment discuss above, the wedge shaped recess 130 is radially offset90° with respect to the tapered sections 122 of the front face 116. Thevertex 132 is rounded to form a substantially cylindrical surface toengage the rounded over surface of the pivot points 120.

A plurality of wire channels 134, 136, 138, 140 are integrally formed inthe link 112 itself or otherwise disposed on the inner surface 142 ofthe link 112. The wire channels are radially spaced at predetermineddistances around the circumference of the link 112. As shown in FIG. 6,channels 136 and 140 are positioned at the pivot points 120, whilechannels 134 and 138 (not shown) are rotated 90° with respect tochannels 136 and 140 and are positioned at the vertex 132 of the wedgeshaped recess 130.

Referring now to FIG. 7, the articulation mechanism 110 is created bystacking a number of links 112 a, 112 b, 112 c, etc., such that that thepivot points 120 of each link 112 are aligned with the vertex 132 of theadjacent link 112. Since the front tapered section 122 and the wedgeshaped recess 130 are perpendicular to each other, each sequentialclement turns the bending plane 90° so bending happens in pairs ofelements.

The control mechanism includes pull-wires 144, 146, 148, 150 and twocontrol cams 152 and 156. The proximal ends of pull-wires 144 and 148are connected to control cam 152 and the distal ends of the pull-wires144 and 148 are connected to the distal end 154 of the articulationmechanism 110. The proximal ends of pull-wires 146 and 150 are connectedto control cam 156 and the distal ends of the pull-wires 146 and 150 areconnected to the distal end 154 of the articulation mechanism 110. Whenthe user rotates the control cam 152 in the clockwise direction asindicated by line D, tension is applied to pull-wire 144, and tension isreleased from pull-wire 148, thereby deflecting the distal end 154 ofthe articulation mechanism 110 in an upward direction. Conversely, whenthe user rotates the control cam 152 in a counter-clockwise direction,tension is applied to pull-wire 148 and released from pull-wire 144,thereby deflecting the distal end 154 in a downward direction. When theuser rotates the control cam 156 in the clockwise direction as indicatedby line E, tension is applied to pull-wire 150, and tension is releasedfrom pull-wire 146, thereby deflecting the distal end 154 of thearticulation mechanism to the right. Conversely, when the user rotatesthe control cam 156 in a counter-clockwise direction, tension is appliedto pull-wire 146 and released from pull-wire 150, thereby deflecting thedistal end 154 to the left.

Referring now to FIG. 8, an articulation mechanism 210 according to analternative embodiment of the present invention is shown. Thearticulation mechanism 210 performs substantially the same function asthe articulation mechanism 10 described above, and therefore likereference numerals preceded by the numeral “2” are used to indicate likeelements.

In this embodiment, a combination of links are used to make thearticulation mechanism 210. The first articulation section 258 closestto the control mechanism is created by stacking a number of links 212 a,212 b, 212 c, etc. such that the pivot points 220 of each link 212 arealigned with the vertex 232 of the adjacent link 212. On the distal sideof link 212 a, a transition link 262 is inserted thereby rotating thebending angle 90°. The second articulation section 260 on the distalside of link 262 is then created by stacking a number of links 212 d,212 e, 212 f, etc. creating two planes of defection.

The control mechanism includes pull-wires 244, 246, 248, 250 and twocontrol cams 252 and 256. The proximal ends of pull-wires 244 and 248are connected to control cam 252 and the distal ends of the pull-wires244 and 248 are connected to the transition link 262. The proximal endsof pull-wires 246 and 250 are connected to control cam 256 and thedistal ends of the pull-wires 246 and 250 are connected to the distalend 254 of the articulation mechanism 210. When the user rotates thecontrol cam 252 in the clockwise direction as indicated by line F,tension is applied to pull-wire 244, and tension is released frompull-wire 248, thereby deflecting the first deflection section 258 ofthe articulation mechanism in an upward direction. Conversely, when theuser rotates the control cam 252 in a counter-clockwise direction,tension is applied to pull-wire 248 and released from pull-wire 244,thereby deflecting the first deflection section 258 in a downwarddirection. When the user rotates the control cam 256 in the clockwisedirection as indicated by line G, tension is applied to pull-wire 250,and tension is released from pull-wire 246, thereby deflecting thesecond deflection section 260 of the articulation mechanism to theright. Conversely, when the user rotates the control cam 256 in acounter-clockwise direction, tension is applied to pull-wire 246 andreleased from pull-wire 250, thereby deflecting the second deflectionsection 260 to the left.

Referring now to FIG. 9, a link 312 according to an alternativeembodiment of the present invention is shown. The link 312 performssubstantially the same function as the link 12 described above, andtherefore like reference numerals preceded by the numeral “3” are usedto indicate like elements.

In this embodiment the front face 316 of the link 312 includes a pair ofoppositely arranged engagement surfaces that bisect the link 312 anddefine a pair of pivot points 320 that engage the corresponding rearface 318 of an adjacent link. The pivot points 320 are rounded overforming substantially cylindrical surfaces that serves as bearings. Thefront face 316 of the link 312 further includes two tapered sections 322that are angled proximally away from the pivot point 320.

The rear thee 318 of the link 312 includes two sloped sections 326 thatare angled distally away from a relatively fiat surface 328 of the rearface 318 forming a wedge shaped recess 330 with a vertex 332 forreceiving the pivot points 320 of an adjacent link. The vertex 332 isrounded to form a substantially cylindrical surface to engage therounded over surface of the pivot points 320.

A plurality of wire channels 334, 336, 338, 340 are integrally formed inthe link 312 itself or otherwise disposed on the inner surface 342 ofthe link 312. The wire channels are radially spaced at predetermineddistances around the circumference of the link 312. As shown in FIG. 9,channels 336 and 340 are positioned at the pivot points 320, whilechannels 334 and 338 are rotated 90° with respect to channels 336 and340 and are positioned at the vertex 332 of the wedge shaped recess 330.

Unlike the embodiment of the link 12 described above, the wire channels336 and 340 are chamfered or otherwise elongated to allow for greaterlateral movement of the pull-wires when the articulation mechanism isdeflected. For example, referring now to FIG. 10, the articulationmechanism 10 created by stacking a number of links 12 a, 12 h, 12 c,etc. is shown in a deflected position. In this deflected position, thewire channels 36 a, 36 b, 36 c, etc. are partially misaligned andpull-wires can jam or be pinched between adjacent links 12.

Referring now also to FIG. 11, the articulation mechanism 310 created bystacking a number of links 312 a, 312 b, 312 c, etc. is shown in adeflected position. In this embodiment, the wire channels 336 a, 336 b,336 c, etc. remain in alignment after deflection due to the chamferingof the wire channels 336. The wire channels 336 can be chamfered at thefront face 316, the rear face 318, or both. Alternatively, the wirechannels 336 can be elongated along their entire length instead ofchamfering at one or both ends.

Additional deflection sections and/or pull-wires could be included inthe control mechanism depending on how many planes of deflection aredesired. The pull-wires 44, 46, 48, 50 are made from stainless steel,polymer filaments, strong textile or synthetic material such as kevlaror nylon, or other metals and alloys such as, for example, Nitinol®,which is a nickel-titanium alloy. The control mechanism may also includehandles, levers, knobs, robotics, a joystick, or other control features,none of which are shown but all of which would be known to thoseknowledgeable about medical devices.

The disclosed embodiments are exemplary. The invention is not limited byor only to the disclosed exemplary embodiments. Also, various changes toand combinations of the disclosed exemplary embodiments are possible andwithin this disclosure.

1. An articulating mechanism for use in a medical device, comprising: aseries of stacked links disposed adjacent to one another and movablewith respect to each other, each link including a front face tapered toa pair of pivot points and a rear face defining a wedge shaped recessfor receiving the pivot points of the adjacent link; and at least onepull-wire for providing tension to the articulation mechanism andholding the adjacent links together.
 2. The articulation mechanism ofclaim 1, wherein the wedge shaped recess is radially offset from thepivot points.
 3. The articulation mechanism of claim 1, furthercomprising a control cam connected to the at least one pull-wire.
 4. Thearticulation mechanism of claim 1, further comprising an outer sleevedisposed on the outside of the articulation mechanism to provide asmooth exterior surface.
 5. The articulation mechanism of claim 4,wherein the outer sleeve comprises a lubricated coating.
 6. Thearticulation mechanism of claim 4, wherein the outer sleeve comprises adrug coating.
 7. The articulation mechanism of claim 1, furthercomprising radiopaque markers.
 8. The articulation mechanism of claim 1,further comprising a radiopaque material.
 9. An articulation mechanismfor use in a medical device, comprising: a series of stacked linksdisposed adjacent to one another and movable with respect to each other,each link including a front face tapered to a pair of pivot points and arear face defining a wedge shaped recess for receiving the pivot pointsof the adjacent link, the wedge shaped recess radially offset from thepivot points; and at least one pull-wire for providing tension to thearticulation mechanism and holding the adjacent links together.
 10. Thearticulation mechanism of claim 9, further comprising a control camconnected to the at least one pull-wire.
 11. The articulation mechanismof claim 9, further comprising an outer sleeve disposed on the outsideof the articulation mechanism to provide a smooth exterior surface. 12.The articulation mechanism of claim 11, wherein the outer sleevecomprises a lubricated coating.
 13. The articulation mechanism of claim11, wherein the outer sleeve comprises a drug coating.
 14. Thearticulation mechanism of claim 9, further comprising radiopaquemarkers.
 15. The articulation mechanism of claim 9, further comprising aradiopaque material.
 16. An articulation mechanism for use in a medicaldevice, comprising: a first articulation section, the first articulationsection includes a first series of stacked links disposed adjacent toone another and movable with respect to each other, each link includinga front face tapered to a pair of pivot points and a rear face defininga wedge shaped recess for receiving the pivot points of the adjacentlink; a second articulation section, the second articulation sectionincludes a second series of stacked links disposed adjacent to oneanother and movable with respect to each other, each link including afront face tapered to a pair of pivot points and a rear face defining awedge shaped recess for receiving the pivot points of the adjacent link,the wedge shaped recesses of the first articulation section radiallyoffset from the wedge shaped recesses of the second articulationsection; and at least one pull-wire for providing tension to thearticulation mechanism and holding the adjacent links together.
 17. Thearticulation mechanism of claim 16, further comprising a control camconnected to the at least one pull-wire.
 18. The articulation mechanismof claim 16, further comprising an outer sleeve disposed on the outsideof the articulation mechanism to provide a smooth exterior surface. 19.The articulation mechanism of claim 18, wherein the outer sleevecomprises a lubricated coating.
 20. The articulation mechanism of claim18, wherein the outer sleeve comprises a drug coating. 21-22. (canceled)